I read another thread that ended on 03/10 in which the OP found that by re-soldering two joints his issue was solved. I'm using an Arduino UNO to install the sketch I'm getting messages I'm not understanding. Several weeks ago, I didn't have any trouble uploading the same sketch to another ATMega 328 with bootloader from from Sparkfun. These last two days have been unhelpful in so far as getting my sketch uploaded.

My Arduino was set to COM4 when I opened it later, and again today. I was getting this message:

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Serial Port COM4 already in use. Try quitting any programs that may be using it.

And then this appears in the window:

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Binary sketch size: 2,748 bytes (of a 32,256 byte maximum)processing.app.SerialException: Serial port 'COM4' already in use. Try quiting any programs that may be using it. at processing.app.Serial.<init>(Serial.java:171) at processing.app.Serial.<init>(Serial.java:77) at processing.app.debug.Uploader.flushSerialBuffer(Uploader.java:77) at processing.app.debug.AvrdudeUploader.uploadViaBootloader(AvrdudeUploader.java:174) at processing.app.debug.AvrdudeUploader.uploadUsingPreferences(AvrdudeUploader.java:67) at processing.app.Sketch.upload(Sketch.java:1671) at processing.app.Sketch.exportApplet(Sketch.java:1627) at processing.app.Sketch.exportApplet(Sketch.java:1599) at processing.app.Editor$DefaultExportHandler.run(Editor.java:2380) at java.lang.Thread.run(Thread.java:619)processing.app.debug.RunnerException: Serial port 'COM4' already in use. Try quiting any programs that may be using it. at processing.app.debug.Uploader.flushSerialBuffer(Uploader.java:101) at processing.app.debug.AvrdudeUploader.uploadViaBootloader(AvrdudeUploader.java:174) at processing.app.debug.AvrdudeUploader.uploadUsingPreferences(AvrdudeUploader.java:67) at processing.app.Sketch.upload(Sketch.java:1671) at processing.app.Sketch.exportApplet(Sketch.java:1627) at processing.app.Sketch.exportApplet(Sketch.java:1599) at processing.app.Editor$DefaultExportHandler.run(Editor.java:2380) at java.lang.Thread.run(Thread.java:619)

"Okay, well, now what" I asked myself. Then, when I reset Arduino 1.0.3 to COM3. I receive this:

I've tried with Blink, too. I could upload both Blink, and my custom sketch to the first chip several weeks ago, but I have 4 more here that can't, although Blink did upload to one of the chips. Uno's LED is flashing on and off in 2 second cycles. I'm powering the UNO through the USB.

Good question. I'd have thought so, too. The first time I used Arduino a few weeks ago, there was no "Ports" heading in my device manager. Installing the Arduino drivers made Ports appear in device manager. It didn't disappear when I disconnected the USB cable from my computer, but when I rebooted, it was gone. Reconnecting the UNO to my machine brought the ports heading back.

Prolific USB-to-Serial Comm Port (COM5); no ports heading appeared until the Arduino was connected. After the device insertion sound, then the Proli<snip>OM5) appeared under Ports. When I last checked, it stays under the Ports heading until reboot.

Thanks for the excellent post; problem solved. Yes, my Arduino is self-made a clone. I have an ATMega168 with no bootloader, and that seems to have been mixed in with the ATMega328s that do have the bootloader. The bigger problem was that I missed a contact when I soldered the socket into place. Once that was soldered, the ATMega328s were simple to load with my sketch. Thanks very much for your help, all of you.